1. Field of the Invention
The present invention relates to a prosthesis of the knee and more particularly, although not exclusively, to a replacement prosthesis, i.e. one used for replacing part of a total prosthesis of the knee already applied to a patient and which must be replaced for some reason. In the case of replacement, it is often necessary to have more solid anchorages of the femoral and tibial elements, with the result that, for fixing the articular element, a long centro-medullary stem of suitable diameter is generally used.
Such a prosthesis may also be employed from the beginning.
2. History of the Related Art
French Patent No. 74 40575 discloses a prosthesis of the knee comprising two elements associated respectively with the femur and with the tibia, the femur element is made in the form of an incurved plate with two condyles, the plate being associated with a centro-medullary stem, while the second or tibia element includes a tibial plate likewise associated with a centro-medullary stem. The centro-medullary stems, secured to the femoral or tibial pieces, must have different characteristics depending on the surgical cases, with the result that their length, diameter, angulation and positioning with respect to the center must vary. Thus is particularly true for the femoral piece.
If it is desired to respond correctly to the surgical cases in question, the surgeon must have a multitude of implants available, which is extremely expensive.
It is an object of the improvements forming the subject matter of the present invention to overcome these drawbacks and to produce a prosthesis incorporating a plurality of components which enables all the desired dimensions of implants to be obtained economically.